I know this would be a problem - as that's exactly how I already trashed circa 10x pairs of lense-inserts for magnifying headsets (which headsets themselves got likewise crapped-up), as well as a couple pairs of reading-type eyeglasses (all of them, fortunately, cheapo units) in the first 5x years of my (serious) return to modelling, starting around 2002! After which I got smart enough to never put my eyewear down anywhere on the bench, itself.
I suppose I could set up a workstation well behind me (or way off to one side), and swivel/slide over, on my rolling stool, to enter the data/commands - and have a second monitor, on a long cable to a wall mount well above the bench. That might keep everything from getting trashed too quickly. Of course, having to look up at a screen, while your hands, tools and the piece being worked, are all down on the bench - plus, maybe even more importantly: losing binocular depth-perception, in the (single-) screen image - will undoubtedly mean you can't actually work under the higher magnification, regardless how high you can make it.
Still, your idea would absolutely allow for constant, and very easy close inspection of the work/progress - an absolutely critical need of mine, and in itself probably already (more than) worth the effort/expense to set it up. Plus, of course there would be all the other benefits: easy review of reference pics and dimensions, right there at the bench, as well as much easier recalculation/checking - even Googling/researching any of these - without having to leave the room.
Definitely worth thinking more about - Thanks for the suggestion, buddy!